Investments

Available-for-Sale Securities

Available-for-sale investments at March 29, 2015 were as follows:



(in thousands)	Cost			Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. government treasuries and agencies securities	$	135,570		$	398	$	(23	)	$	135,945
Money market funds	55,578			—		—			55,578
Asset-backed securities	31,830			9		(9		)	31,830
Corporate bonds	245,229			567		(121		)	245,675
International government bonds	1,010			—		(4		)	1,006
Corporate commercial paper	4,999			—		—			4,999
Bank deposits	16,915			—		—			16,915
Repurchase agreements	191			—		—			191
Municipal bonds	6,001			45		(2		)	6,044
Total available-for-sale investments	497,323			1,019		(159		)	498,183
Less amounts classified as cash equivalents	(60,068		)	—		—			(60,068		)
Short-term investments	$	437,255		$	1,019	$	(159	)	$	438,115

Available-for-sale investments at March 30, 2014 were as follows:



(in thousands)	Cost			Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. government treasuries and agencies securities	$	112,268		$	76	$	(91	)	$	112,253
Money market funds	53,430			—		—			53,430
Asset-backed securities	22,330			11		(9		)	22,332
Corporate bonds	199,598			335		(127		)	199,806
International government bonds	3,023			—		(9		)	3,014
Corporate commercial paper	6,246			—		—			6,246
Bank deposits	18,538			—		—			18,538
Repurchase agreements	46			—		—			46
Municipal bonds	9,196			32		(18		)	9,210
Total available-for-sale investments	424,675			454		(254		)	424,875
Less amounts classified as cash equivalents	(62,671		)	—		—			(62,671		)
Short-term investments	$	362,004		$	454	$	(254	)	$	362,204

The cost and estimated fair value of available-for-sale debt securities at March 29, 2015, by contractual maturity, were as follows:



(in thousands)	Amortized Cost		Estimated Fair Value
Due in 1 year or less	$	153,753	$	153,823
Due in 1-2 years	132,241		132,529
Due in 2-5 years	211,329		211,831
Total investments in available-for-sale debt securities	$	497,323	$	498,183

The cost and estimated fair value of available-for-sale debt securities at March 30, 2014, by contractual maturity, were as follows:



(in thousands)	Amortized Cost		Estimated Fair Value
Due in 1 year or less	$	173,850	$	173,891
Due in 1-2 years	101,275		101,378
Due in 2-5 years	149,550		149,606
Total investments in available-for-sale debt securities	$	424,675	$	424,875

The following table shows the gross unrealized losses and fair value of the Company’s investments with unrealized losses as of March 29, 2015, aggregated by investment category and length of time that individual securities have been in a continuous loss position.



	Less Than 12 Months					12 Months or Greater				Total
(in thousands)	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Corporate bonds	$	67,367	$	(121	)	$	—	$	—	$	67,367	$	(121	)
Asset-backed securities	17,736		(9		)	—		—		17,736		(9		)
U.S. government treasuries and agencies securities	18,478		(23		)	—		—		18,478		(23		)
Municipal bonds	1,001		(2		)	—		—		1,001		(2		)
International government bonds	1,006		(4		)	—		—		1,006		(4		)
Total	$	105,588	$	(159	)	$	—	$	—	$	105,588	$	(159	)

The following table shows the gross unrealized losses and fair value of the Company’s investments with unrealized losses, as of March 30, 2014, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position.



	Less Than 12 Months					12 Months or Greater				Total
(in thousands)	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Corporate bonds	$	52,783	$	(127	)	$	—	$	—	$	52,783	$	(127	)
Asset-backed securities	11,156		(9		)					11,156		(9		)
U.S. government treasuries and agencies securities	36,403		(91		)	—		—		36,403		(91		)
Municipal bonds	4,000		(18		)	—		—		4,000		(18		)
International government bonds	3,014		(9		)	—		—		3,014		(9		)
Total	$	107,356	$	(254	)	$	—	$	—	$	107,356	$	(254	)

Currently, a significant portion of the Company’s available-for-sale investments that it holds are high grade instruments. As of March 29, 2015, the unrealized losses on the Company’s available-for-sale investments represented an insignificant amount in relation to its total available-for-sale portfolio. Substantially all of the Company’s unrealized losses on its available-for-sale marketable debt instruments can be attributed to fair value fluctuations in an unstable credit environment that resulted in a decrease in the market liquidity for debt instruments. Because the Company has the ability to hold these investments until a recovery of fair value, which may be maturity, the Company did not consider these investments to be other-than-temporarily impaired at March 29, 2015 or March 30, 2014.

Non-marketable Equity Securities

The Company accounts for its equity investments in privately held companies under the cost method. These investments are subject to periodic impairment review and measured and recorded at fair value when they are deemed to be other-than-temporarily impaired. In determining whether a decline in value of its investment has occurred and is other than temporary, an assessment was made by considering available evidence, including the general market conditions, the investee’s financial condition, near-term prospects, market comparables and subsequent rounds of financing. The valuation also takes into account the investee’s capital structure, liquidation preferences for its capital and other economic variables. The valuation methodology for determining the decline in value of non-marketable equity securities is based on inputs that require management's judgment.

During fiscal 2015, the Company purchased common stock of a privately-held company for $4.0 million. This investment (included in Other Assets on the Consolidated Balance Sheet) is accounted for as a cost-method investment, as the Company owns less than 20% of the voting securities and does not have the ability to exercise significant influence over operating and financial policies of the entity.

The Company did not recognize any impairment loss in fiscal 2015 and 2014. During fiscal 2013, the Company determined that the carrying values of two of its non-marketable equity securities were impaired and recorded a $1.7 million other-than-temporary impairment loss during the period. The aggregate carrying value of the Company’s non-marketable equity securities was $4.0 million and zero as of March 29, 2015 and March 30, 2014, respectively.